Mortality and Resource Use Among Individuals With Chronic Kidney Disease or Cancer in Alberta, Canada, 2004-2015.

Importance: Although the public is aware that cancer is associated with excess mortality and adverse outcomes, the clinical consequences of chronic kidney disease (CKD) are not well understood. Objective: To compare the clinical consequences of incident severe CKD and the first diagnosis with a malignant tumor, focusing on the 10 leading causes of cancer in men and women residing in Canada. Design, Setting, and Participants: This population-based cohort study enrolled individuals aged 19 years and older with severe CKD or certain types of cancer between 2004 and 2015 in Alberta, Canada. Data were analyzed in November 2021. Exposures: Individuals were categorized as having severe CKD (based on estimated glomerular filtration rate <30 mL/min/1.73 m2 or nephrotic albuminuria without dialysis or kidney transplantation) or nonmetastatic or metastatic cancer (defined by a diagnosis of lung, breast, colorectal, prostate, bladder, thyroid, kidney or renal pelvis, uterus, pancreas, or oral cancer). Main Outcomes and Measures: All-cause mortality, number of hospitalizations, total number of hospital days, and placement into long-term care were calculated after diagnosis. Results: Of 200 494 individuals in the cohort (104 559 women [52.2%]; median [IQR] age, 66.8 [55.9-77.7] years), 51 159 (25.5%) had incident severe CKD, 115 504 (57.6%) had nonmetastatic cancer, and 33 831 (16.9%) had metastatic cancer. Kaplan-Meier 1-year survival was 83.3% (95% CI, 83.0%-83.6%) for patients with CKD, 91.2% (95% CI, 91.0%-91.4%) for patients with nonmetastatic cancer, and 52.8% (95% CI, 52.2%-53.3%) for patients with metastatic cancer. Kaplan-Meier 5-year survival was 54.6% (95% CI, 54.2%-55.1%) for patients with CKD, 76.6% (95% CI, 76.3%-76.8%) for patients with nonmetastatic cancer, and 33.9% (95% CI, 33.3%-34.4%) for patients with metastatic cancer. Compared with nonmetastatic cancer, the age-, sex-, and comorbidity-adjusted relative rate of death was similar for CKD (adjusted relative rate, 1.00; 95% CI, 0.97-1.03; P = .92) during the first year of follow-up and was higher for CKD at years 1 to 5 (adjusted relative rate 1.23; 95% CI, 1.19-1.26). During the first year of follow-up, for patients with CKD, adjusted rates of placement in long-term care (adjusted relative rate, 0.88; 95% CI, 0.82-0.94) and hospitalization (adjusted relative rate, 0.65; 95% CI, 0.64-0.66) were lower than rates for patients with nonmetastatic cancer; however, those rates were higher for the CKD group than for the nonmetastatic cancer group during years 1 to 5 (long-term care placement, adjusted relative rate, 1.36; 95% CI, 1.29-1.43; hospitalization, adjusted relative rate, 1.55; 95% CI, 1.52-1.58). As expected, adjusted rates of long-term care placement and hospitalization were higher for patients with metastatic cancer than for the other 2 groups. Conclusions and Relevance: In this study, mortality, hospitalization, and likelihood of placement into long-term care were similar for CKD and nonmetastatic cancer. These data highlight the importance of CKD as a public health problem.

The real-world cost-effectiveness of bariatric surgery for the treatment of severe obesity: a cost-utility analysis.

BACKGROUND: Severe obesity is associated with adverse health outcomes and increased risk of death. This study evaluates the real-world cost-utility of therapy for severe obesity, from the publicly funded health care system and societal perspectives. METHODS: We conducted a cost-utility analysis using primary data from a prospective observational cohort of adults living with severe obesity (BMI ≥ 35 kg/m2 and a major medical comorbidity or BMI ≥ 40 kg/m2) who were enrolled in a regional obesity program over 2 years. We extrapolated 10-year and lifetime Markov models, validated and supplemented with literature sources, to compare medical, surgical and standard care therapies. We performed deterministic and probabilistic sensitivity analyses. RESULTS: The cohort included 500 adults living with severe obesity, 150 of whom received laparoscopic surgical therapy. From a publicly funded health system perspective, at 2 years, surgical therapy had an incremental cost-effectiveness ratio (ICER) of $54 456 per quality-adjusted life-year (QALY) compared with standard care therapy. Over a lifetime, it had an ICER of $14 056 per QALY. From the societal perspective, at 2 years, surgical therapy had an ICER of $340 per QALY; over a lifetime, it was the dominant option. The results were robust to sensitivity analysis. INTERPRETATION: From a public health care perspective, surgery for severe obesity is cost effective, and when approached from a societal perspective, it becomes cost saving. Real-world data support using surgical therapy for severe obesity, and our results contribute to the health economic and clinical literature with regard to a robust analysis from a societal perspective.

Screening for Asymptomatic Coronary Artery Disease in Waitlisted Kidney Transplant Candidates: A Cost-Utility Analysis.

RATIONALE & OBJECTIVE: On account of the high prevalence of cardiovascular disease in patients with kidney failure, clinical practice guidelines recommend regular screening for asymptomatic coronary artery disease (CAD) in patients on the kidney transplant waitlist. To date, the cost-effectiveness of such screening has not been evaluated. A Canadian-Australasian randomized controlled trial of screening kidney transplant candidates for CAD (CARSK) is currently is being conducted to answer this question. We conducted a cost-utility analysis to determine, before completion of the trial, the cost-effectiveness of no further screening versus regular screening for asymptomatic CAD and to evaluate potential influential variables that may affect results of the economic evaluation. STUDY DESIGN: A modeled cost-utility analysis. SETTING & POPULATION: A theoretical cohort of adult Australian and New Zealand kidney transplant candidates on the waitlist. INTERVENTION: No further screening for asymptomatic CAD versus regular protocolized screening (annual or second yearly) for CAD after kidney transplant waitlisting. OUTCOMES: Incremental cost-effectiveness ratio, reported as cost per quality-adjusted life-year (QALY). MODEL, PERSPECTIVES, & TIMEFRAME: Markov microsimulation model, health system perspective and over a lifetime horizon. RESULTS: In the base case, the incremental cost-effectiveness ratio of no further screening was $11,122 per QALY gained when compared with regular screening. No further screening increased survival by 0.49 life-year or 0.35 QALY. One-way sensitivity analyses identified the costs of transplantation in the first year and CAD prevalence as the most influential variables. Probabilistic sensitivity analyses showed that 94% of the simulations were cost-effective below a willingness-to-pay threshold of $50,000 per QALY gained. LIMITATIONS: Rates of cardiovascular events in waitlisted candidates and transplant recipients are limited in the contemporary era. The results may not be generalizable to populations outside Australia and New Zealand. CONCLUSIONS: No further screening for CAD after waitlisting is likely to be cost-effective and may improve survival. Precision around CAD prevalence estimates and health care resource use will reduce existing uncertainty.

Secular Changes in Mortality and Hospitalization over Time in People with Kidney Failure or Severe CKD as Compared with Other Noncommunicable Diseases.

BACKGROUND: Few new treatments have been developed for kidney failure or CKD in recent years, leading to perceptions of slower improvement in outcomes associated with CKD or kidney failure than for other major noncommunicable diseases. METHODS: Our retrospective cohort study included 548,609 people with an incident noncommunicable disease, including cardiovascular diseases, diabetes, various cancers, and severe CKD or kidney failure treated with renal replacement (KF-RRT), treated in Alberta, Canada, 2004-2015. For each disease, we assessed presence or absence of 8 comorbidities; we also compared secular trends in relative (compared to a referent year of 2004) and absolute risks of mortality and mean annual days in the hospital associated with each disease after 1 year and 5 years. RESULTS: Comorbidities increased significantly in number over time for all noncommunicable diseases except diabetes, and increased most rapidly for CKD and KF-RRT. Significant but relatively small reductions over time in the risk ratio of mortality at 1 year occurred for nearly all noncommunicable diseases. Secular trends in the absolute risk of mortality were similar; CKD and KF-RRT had a relatively favorable ranking at 1 year. Breast cancer, KF-RRT, diabetes, and colorectal cancer displayed the largest relative reductions in number of hospital days at 1 year. Significant absolute reductions in the number of hospital days were observed for both KF-RRT and CKD; the former had the highest absolute reduction among all noncommunicable diseases. Results were similar at 5 years. CONCLUSIONS: We observed secular reductions in mortality and annual hospital days at 1 year and 5 years among incident patients with KF-RRT and severe CKD, as well as several other common noncommunicable diseases.

Canadian-Australasian Randomised trial of screening kidney transplant candidates for coronary artery disease-A trial protocol for the CARSK study.

Transplantation is the preferred treatment for patients with kidney failure, but the need exceeds the supply of transplantable kidneys, and patients routinely wait >5 years on dialysis for a transplant. Coronary artery disease (CAD) is common in kidney failure and can exclude patients from transplantation or result in death before or after transplantation. Screening asymptomatic patients for CAD using noninvasive tests prior to wait-listing and at regular intervals (ie, annually) after wait-listing until transplantation is the established standard of care and is justified by the need to avoid adverse patient outcomes and loss of organs. Patients with abnormal screening tests undergo coronary angiography, and those with critical stenoses are revascularized. Screening is potentially harmful because patients may be excluded or delayed from transplantation, and complications after revascularization are more frequent in this population. CARSK will test the hypothesis that eliminating screening tests for occult CAD after wait-listing is not inferior to regular screening for the prevention of major adverse cardiac events defined as the composite of cardiovascular death, nonfatal myocardial infarction, urgent revascularization, and hospitalization for unstable angina. Secondary outcomes include the transplant rate, safety measures, and the cost-effectiveness of screening. Enrolment of 3,306 patients over 3 years is required, with patients followed for up to 5 years during wait-listing and for 1 year after transplantation. By validating or refuting the use of screening tests during wait-listing, CARSK will ensure judicious use of health resources and optimal patient outcomes.

Red cell distribution width associations with clinical outcomes: A population-based cohort study.

IMPORTANCE: Higher levels of red cell distribution width (RDW) are associated with adverse outcomes, especially in selected cohorts with or at risk for chronic disease. Whether higher RDW or the related parameter standard deviation of the red blood cell distribution (SD-RBC) can predict a broader range of outcomes in the general population is unknown. OBJECTIVE: To evaluate the association of RDW and SD-RBC with the risk of adverse outcomes in people from the general population. DESIGN: Population-based retrospective cohort study. SETTING: Health care system in a Canadian province (Alberta). PARTICIPANTS: All 3,156,863 adults living in Alberta, Canada with at least one measure of RDW and SD-RBC between 2003 and 2016. Data were analyzed in September 2018. EXPOSURE: RDW and SD-RBC, classified into percentiles (<1, 1-5, 5-25, 25-75, 75-95, 95-99, >99). MAIN OUTCOMES: All-cause death, first myocardial infarction, first stroke or transient ischemic attack, placement into long-term care (LTC), progression to renal replacement therapy (initiation of chronic dialysis or pre-emptive kidney transplantation), incident solid malignancy, and first hospitalization during follow-up. RESULTS: Over median follow-up of 6.8 years, 209,991 of 3,156,863 participants (6.7%) died. The risk of death increased with increasing RDW percentile. After adjustment, and compared to RDW in the 25th to 75th percentiles, the risk of death was lower for participants in the <25th percentiles but higher for participants in the 75th-95th percentiles (HR 1.42, 95% CI 1.40,1.43), the 95th-99th percentiles (HR 1.86, 95% CI 1.83,1.89) and the >99th percentile (HR 2.18, 95% CI 2.12,2.23). Similar results were observed for MI, stroke/TIA, incident cancer, hospitalization and LTC placement, but no association was found between RDW and ESRD. Findings were generally similar for SD-RBC, except that all associations tended to be stronger than for RDW, and both lower and higher values of SD-RBC were independently associated with ESRD. CONCLUSION AND RELEVANCE: RDW and SD-RBC may be useful as prognostic markers for people in the general population, especially for outcomes related to chronic illness. SD-RBC may be superior to RDW.

Comorbidity as a driver of adverse outcomes in people with chronic kidney disease.

Chronic kidney disease (CKD) is associated with poor outcomes, perhaps due to a high burden of comorbidity. Most studies of CKD populations focus on concordant comorbidities, which cause CKD (such as hypertension and diabetes) or often accompany CKD (such as heart failure or coronary disease). Less is known about the burden of mental health conditions and discordant conditions (those not concordant but still clinically relevant, like dementia or cancer). Here we did a retrospective population-based cohort study of 530,771 adults with CKD residing in Alberta, Canada between 2003 and 2011. Validated algorithms were applied to data from the provincial health ministry to assess the presence/absence of 29 chronic comorbidities. Linkage between comorbidity burden and adverse clinical outcomes (mortality, hospitalization or myocardial infarction) was examined over median follow-up of 48 months. Comorbidities were classified into three categories: concordant, mental health/chronic pain, and discordant. The median number of comorbidities was 1 (range 0-15) but a substantial proportion of participants had 3 and more, or 5 and more comorbidities (25 and 7%, respectively). Concordant comorbidities were associated with excess risk of hospitalization, but so were discordant comorbidities and mental health conditions. Thus, discordant comorbidities and mental health conditions as well as concordant comorbidities are important independent drivers of the adverse outcomes associated with CKD.

Methods for identifying 30 chronic conditions: application to administrative data.

BACKGROUND: Multimorbidity is common and associated with poor clinical outcomes and high health care costs. Administrative data are a promising tool for studying the epidemiology of multimorbidity. Our goal was to derive and apply a new scheme for using administrative data to identify the presence of chronic conditions and multimorbidity. METHODS: We identified validated algorithms that use ICD-9 CM/ICD-10 data to ascertain the presence or absence of 40 morbidities. Algorithms with both positive predictive value and sensitivity ≥70% were graded as "high validity"; those with positive predictive value ≥70% and sensitivity <70% were graded as "moderate validity". To show proof of concept, we applied identified algorithms with high to moderate validity to inpatient and outpatient claims and utilization data from 574,409 people residing in Edmonton, Canada during the 2008/2009 fiscal year. RESULTS: Of the 40 morbidities, we identified 30 that could be identified with high to moderate validity. Approximately one quarter of participants had identified multimorbidity (2 or more conditions), one quarter had a single identified morbidity and the remaining participants were not identified as having any of the 30 morbidities. CONCLUSIONS: We identified a panel of 30 chronic conditions that can be identified from administrative data using validated algorithms, facilitating the study and surveillance of multimorbidity. We encourage other groups to use this scheme, to facilitate comparisons between settings and jurisdictions.

Weight loss required by the severely obese to achieve clinically important differences in health-related quality of life: two-year prospective cohort study.

BACKGROUND: Guidelines and experts describe 5% to 10% reductions in body weight as 'clinically important'; however, it is not clear if 5% to 10% weight reductions correspond to clinically important improvements in health-related quality of life (HRQL). Our objective was to calculate the amount of weight loss required to attain established minimal clinically important differences (MCIDs) in HRQL, measured using three validated instruments. METHODS: Data from the Alberta Population-based Prospective Evaluation of Quality of Life Outcomes and Economic Impact of Bariatric Surgery (APPLES) study, a population-based, prospective Canadian cohort including 150 wait-listed, 200 medically managed and 150 surgically treated patients were examined. Two-year changes in weight and HRQL measures (Short-Form (SF)-12 physical (PCS; MCID = 5) and mental (MCS; MCID = 5) component summary score, EQ-5D Index (MCID = 0.03) and Visual Analog Scale (VAS; MCID = 10), Impact of Weight on Quality of Life (IWQOL)-Lite total score (MCID = 12)) were calculated. Separate multivariable linear regression models were constructed within medically and surgically treated patients to determine if weight changes achieved HRQL MCIDs. Pooled analysis in all 500 patients was performed to estimate the weight reductions required to achieve the pre-defined MCID for each HRQL instrument. RESULTS: Mean age was 43.7 (SD 9.6) years, 88% were women, 92% were white, and mean initial body mass index was 47.9 (SD 8.1) kg/m2. In surgically treated patients (two-year weight loss = 16%), HRQL MCIDs were reached for all instruments except the SF-12 MCS. In medically managed patients (two-year weight loss = 3%), MCIDs were attained in the EQ-index but not the other instruments. In all patients, percent weight reductions to achieve MCIDs were: 23% (95% confidence interval (CI): 17.5, 32.5) for PCS, 25% (17.5, 40.2) for MCS, 9% (6.2, 15.0) for EQ-Index, 23% (17.3, 36.1) for EQ-VAS, and 17% (14.1, 20.4) for IWQOL-Lite total score. CONCLUSIONS: Weight reductions to achieve MCIDs for most HRQL instruments are markedly higher than the conventional threshold of 5% to 10%. Surgical, but not medical treatment, consistently led to clinically important improvements in HRQL over two years. TRIAL REGISTRATION: Clinicaltrials.gov NCT00850356.

Potentially preventable hospitalization as a complication of CKD: a cohort study.

BACKGROUND: Ambulatory care-sensitive conditions have been described as those that (if appropriately managed in an outpatient setting) generally do not require subsequent hospitalization. Our goal was to identify clinical populations of people who are at the highest risk of ambulatory care-sensitive conditions related to chronic kidney disease (CKD). STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: 2,003,054 adults (including 238,747 adults with CKD) residing in Alberta, Canada, with at least one serum creatinine measurement between 2002 and 2009. PREDICTORS: Estimated glomerular filtration rate and albuminuria categories, CKD status, demographics, and clinical characteristics. OUTCOMES: Hospitalization with heart failure, hyperkalemia, volume overload, or malignant hypertension. MEASUREMENTS: We used the Alberta Kidney Disease Network database, which incorporates data from Alberta Health, the Northern and Southern Alberta Renal Programs, and clinical laboratories in Alberta. RESULTS: During a median follow-up of 4.1 years, 43,863 participants were hospitalized for heart failure; 6,274 participants, for hyperkalemia; 2,035 participants, for volume overload; and 481 participants, for malignant hypertension. All 4 conditions were more common at lower estimated glomerular filtration rates and in the presence of albuminuria. In the subset of participants with CKD, heart failure, hyperkalemia, and volume overload were associated most strongly with older age, diabetes, chronic liver disease, and prior heart failure. Malignant hypertension was associated with prior hypertension, aboriginal status, and peripheral vascular disease. Remote-dwelling participants were more likely to experience heart failure and malignant hypertension than those living closer to providers. LIMITATIONS: No data for medication use or potentially important process-based outcomes for study participants. CONCLUSIONS: Our findings suggest that future studies seeking to determine how to prevent ambulatory care-sensitive conditions in people with CKD should target remote dwellers and those with comorbid conditions such as concomitant heart failure and liver disease.

Predictors of health-related quality of life in 500 severely obese patients.

OBJECTIVE: To characterize health-related quality of life (HRQL) impairment in severely obese subjects, using several validated instruments. METHODS: A cross-sectional analysis of 500 severely obese subjects was completed. Short-Form (SF)-12 [Physical (PCS) and Mental (MCS) component summary scores], EuroQol (EQ)-5D [Index and Visual Analog Scale (VAS)], and Impact of Weight on Quality of Life (IWQOL)-Lite were administered. Multivariable linear regression models were performed to identify independent predictors of HRQL. RESULTS: Increasing BMI was associated with lower PCS (-1.33 points per 5 kg/m(2) heavier; P < 0.001), EQ-index (-0.02; P < 0.001), EQ-VAS (-1.71; P = 0.003), and IWQOL-Lite (-3.72; P = 0.002), but not MCS (P = 0.69). The strongest predictors (all P < 0.005) for impairment in each instrument were: fibromyalgia for PCS (-5.84 points), depression for MCS (-7.49 points), stroke for EQ-index (-0.17 points), less than full-time employment for EQ-VAS (-7.06 points), and coronary disease for IWQOL-Lite (-10.86 points). Chronic pain, depression, and sleep apnea were associated with reduced HRQL using all instruments. CONCLUSION: The clinical impact of BMI on physical and general HRQL was small, and mental health scores were not associated with BMI. Chronic pain, depression, and sleep apnea were consistently associated with lower HRQL.

Prioritization and willingness to pay for bariatric surgery: the patient perspective.

BACKGROUND: Access to publicly funded bariatric surgery is limited, potential candidates face lengthy waits, and no universally accepted prioritization criteria exist. We examined patients' perspectives regarding prioritization for surgery. METHODS: We surveyed consecutively recruited patients awaiting bariatric surgery about 9 hypothetical scenarios describing patients waiting for surgery. Respondents were asked to rank the priority of these hypothetical patients on the wait list relative to their own. Scenarios examined variations in age, clinical severity, functional impairment, social dependence and socioeconomic status. Willingness to pay for faster access was assessed using a 5-point ordinal scale and analyzed using multivariable logistic regression. RESULTS: The 99 respondents had mean age of 44.7 ± 9.9 years, 76% were women, and the mean body mass index was 47.3 ± SD 7.6. The mean wait for surgery was 34.4 ± 9.4 months. Respondents assigned similar priority to hypothetical patients with characteristics identical to theirs (p = 0.22) and higher priority (greater urgency) to those exhibiting greater clinical severity (p < 0.001) and functional impairment (p = 0.003). Lower priority was assigned to patients at the extremes of age (p = 0.006), on social assistance (p < 0.001) and of high socioeconomic status (p < 0.001). Most (85%) respondents disagreed with payment to expedite access, although participants earning more than $80 000/year were less likely to disagree. CONCLUSION: Most patients waiting for bariatric surgery consider greater clinical severity and functional impairments related to obesity to be important prioritization indicators and disagreed with paying for faster access. These findings may help inform future efforts to develop acceptable prioritization strategies for publicly funded bariatric surgery.

CONTEXTE: Les régimes publics donnent un accès limité à la chirurgie bariatrique; les candidats potentiels font face à des attentes prolongées et il n'existe pas de critères de priorisation universellement acceptés. Nous avons analysé le point de vue des patients relativement à la priorisation des candidats à la chirurgie. MÉTHODES: Nous avons recruté consécutivement des patients en attente de chirurgie bariatrique et nous les avons interrogés au sujet de 9 scénarios hypothétiques décrivant des patients en attente de chirurgie. Nous avons demandé aux répondants de classer ces patients hypothétiques par ordre de priorité sur la liste d'attente par rapport à la priorité de leur propre cas. Les scénarios présentaient des variations d'âge, de gravité de l'état clinique, d'atteintes fonctionnelles, de dépendance sociale et de statut socioéconomique. Nous avons déterminé au moyen d'une échelle ordinale en 5 points si les patients étaient disposés à payer pour accéder plus rapidement au traitement et nous avons analysé les réponses par régression logistique multivariée. RÉSULTATS: Les 99 répondants avaient en moyenne 44,7 ± 9,9 ans, 76 % étaient des femmes dont l'indice de masse corporelle moyen était de 47,3 ± 7,6. Le temps d'attente moyen pour la chirurgie était de 34,4 ± 9,4 mois. Les répondants ont assigné une priorité similaire aux patients hypothétiques dont les caractéristiques étaient identiques aux leurs (p = 0,22) et une priorité plus élevée (urgence supérieure) à ceux qui présentaient un état clinique plus grave (p < 0,001) et une détérioration fonctionnelle plus prononcée (p = 0,003). Une priorité moins grande a été assignée aux patients qui se trouvaient aux 2 extrémités de l'éventail des âges (p = 0,006), aux bénéficiaires de l'aide sociale (p < 0,001) et aux personnes de statut socioéconomique élevé (p < 0,001). La plupart des répondants (85 %) se sont exprimés contre le paiement pour accélérer l'accès, même si les participants qui gagnaient plus de 80 000 $ par année étaient moins enclins à s'y opposer. CONCLUSION: La plupart des patients en attente d'une chirurgie bariatrique considèrent que la gravité de l'état clinique et les atteintes fonctionnelles associées à l'obésité sont d'importants indicateurs de priorisation et s'opposent à payer pour un accès plus rapide à l'intervention. Ces observations pourraient guider une éventuelle mise au point de stratégies de priorisation pour la chirurgie bariatrique financée par les régimes publics.

Kidney stones and cardiovascular events: a cohort study.

BACKGROUND AND OBJECTIVES: Kidney stones are common in general clinical practice, and their prevalence is increasing. Kidney stone formers often have risk factors associated with atherosclerosis, but it is uncertain whether having a kidney stone is associated with higher risk of cardiovascular events. This study sought to assess the association between one or more kidney stones and the subsequent risk of cardiovascular events. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Cohort study of 3,195,452 people aged≥18 years registered in the universal health care system in Alberta, Canada, between 1997 and 2009 (median follow-up of 11 years). People undergoing dialysis or with a kidney transplant at baseline were excluded. The primary outcome was the first acute myocardial infarction (AMI) during follow-up. We also considered other cardiovascular events, including death due to coronary heart disease, percutaneous transluminal coronary angioplasty (PTCA), coronary artery bypass grafting (CABG), and stroke. RESULTS: In total, 25,532 (0.8%) participants had at least one kidney stone, and 91,465 (3%) individuals had at least one cardiovascular event during follow-up. Compared with people without kidney stones and after adjustment for cardiovascular risk factors and other potential confounders, people who had at least one kidney stone had a higher risk of subsequent AMI (adjusted hazard ratio [HR], 1.40; 95% confidence interval [95% CI], 1.30 to 1.51), PTCA/CABG (HR, 1.63; 95% CI, 1.51 to 1.76), and stroke (HR, 1.26; 95% CI, 1.12 to 1.42). The magnitude of the excess risk associated with a kidney stone appeared more pronounced for younger people than for older people (P<0.001) and for women than men (P=0.01). CONCLUSIONS: The occurrence of a kidney stone is associated with a higher risk of cardiovascular events, including AMI, PTCA/CABG, and stroke.

A simple prediction rule for all-cause mortality in a cohort eligible for bariatric surgery.

IMPORTANCE: Current eligibility criteria for bariatric surgery use arbitrarily chosen body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared) thresholds, an approach that has been criticized as arbitrary and lacking evidence. OBJECTIVES: To verify the importance of BMI as a mortality predictor, to identify other important mortality predictors, and to construct a mortality prediction rule in a population eligible for bariatric surgery. DESIGN: We studied individuals from a population-representative register who met contemporary eligibility criteria for bariatric surgery (BMI, ≥35.0 alone or 30.0-34.9 with an obesity-related comorbidity) from January 1, 1988, through December 31, 1998. We used binary logistic regression to construct a parsimonious model and a clinical prediction rule for 10-year all-cause mortality. SETTING: The United Kingdom General Practice Research Database, a population-representative primary care registry. PARTICIPANTS: Fifteen thousand three hundred ninety-four patients aged 18 to 65 years. EXPOSURE: Bariatric surgery. MAIN OUTCOME AND MEASURE: Ten-year all-cause mortality. RESULTS: Mean (SD) age was 46.9 (11.9) years, BMI was 36.2 (5.5), and 63.2% of the patients were women. All-cause mortality was 2.1%, and mean follow-up duration was 9.9 years. The final model, which included age (odds ratio, 1.09 per year [95% CI, 1.07-1.10]), type 2 diabetes mellitus (2.25 [1.76-2.87]), current smoking (1.62 [1.28-2.06]), and male sex (1.50 [1.20-1.87]), had a C statistic of 0.768. Although BMI significantly predicted mortality (odds ratio, 1.03 per unit [95% CI, 1.01-1.05]), it did not improve model discrimination or calibration. We divided clinical prediction rule scoring into 4 tiers. All-cause mortality was 0.2% in tier 1, 0.9% in tier 2, 2.0% in tier 3, and 5.2% in tier 4. CONCLUSIONS AND RELEVANCE: All-cause 10-year mortality in obese individuals eligible for bariatric surgery can be estimated using a simple 4-variable prediction rule based on age, sex, smoking, and diabetes mellitus. Body mass index was not an important mortality predictor. Further work is needed to define low, moderate, and high absolute risk thresholds and to provide external validation.

Prevalence and predictors of self-reported sexual abuse in severely obese patients in a population-based bariatric program.

BACKGROUND: Sexual abuse may be associated with poorer weight loss outcomes following bariatric treatment. Identifying predictors of abuse would enable focused screening and may increase weight management success. METHODS: We analyzed data from 500 consecutively recruited obese subjects from a population-based, regional bariatric program. The prevalence of self-reported sexual abuse was ascertained using a single interview question. Health status was measured using a visual analogue scale (VAS). Multivariable logistic regression was performed to identify sexual abuse predictors. RESULTS: The mean age was 43.7 y (SD 9.6), 441 (88.2%) were females, 458 (91.8%) were white, and the mean body mass index (BMI) was 47.9 kg/m(2) (SD 8.1). The self-reported prevalence of past abuse was 21.8% (95% CI 18.4-25.4%). Abused subjects had worse health status (VAS score 53.1 (SD 21.2) versus 58.0 (SD 20.1), P = 0.03). BMI was not associated with abuse (P > 0.5). Age, sex, BMI, and covariate-adjusted independent predictors of abuse included alcohol addiction (adjusted odds ratio 15.8; 95% CI 4.0-62.8), posttraumatic stress disorder (4.9; 2.5-9.5), borderline personality (3.8; 1.0-13.8), depression (2.4; 1.3-4.3), and lower household income (3.4; 1.6-7.0). CONCLUSIONS: Abuse was common amongst obese patients managed in a population-based bariatric program; alcohol addiction, psychiatric comorbidities, and low-income status were highly associated with sexual abuse.

Health care costs in people with diabetes and their association with glycemic control and kidney function.

OBJECTIVE: To determine the association between laboratory-derived measures of glycemic control (HbA1c) and the presence of renal complications (measured by proteinuria and estimated glomerular filtration rate [eGFR]) with the 5-year costs of caring for people with diabetes. RESEARCH DESIGN AND METHODS: We estimated the cumulative 5-year cost of caring for people with diabetes using a province-wide cohort of adults with diabetes as of 1 May 2004. Costs included physician visits, hospitalizations, ambulatory care (emergency room visits, day surgery, and day medicine), and drug costs for people >65 years of age. Using linked laboratory and administrative clinical and costing data, we determined the association between baseline glycemic control (HbA1c), proteinuria, and kidney function (eGFR) and 5-year costs, controlling for age, socioeconomic status, duration of diabetes, and comorbid illness. RESULTS: We identified 138,662 adults with diabetes. The mean 5-year cost of diabetes in the overall cohort was $26,978 per patient, excluding drug costs. The mean 5-year cost for the subset of people >65 years of age, including drug costs, was $44,511 (Canadian dollars). Cost increased with worsening kidney function, presence of proteinuria, and suboptimal glycemic control (HbA1c >7.9%). Increasing age, Aboriginal status, socioeconomic status, duration of diabetes, and comorbid illness were also associated with increasing cost. CONCLUSIONS: The cost of caring for people with diabetes is substantial and is associated with suboptimal glycemic control, abnormal kidney function, and proteinuria. Future studies should assess if improvements in the management of diabetes, assessed with laboratory-derived measurements, result in cost reductions.

Economic analysis of epoetin alfa in critically ill trauma patients.

BACKGROUND: Recent randomized control trials (RCTs) suggest that epoetin alfa reduces mortality in critically ill trauma patients; however, epoetin alfa is also costly and associated with adverse events. This study evaluates the cost-effectiveness of epoetin alfa in surgical trauma patients in an intensive care unit setting. METHODS: We constructed a decision analytic model to compare adjunctive use of epoetin alfa with standard care in trauma patients from the perspective of a Canadian payer. Baseline risks of events, relative efficacy, and resource use were obtained from RCTs and observational studies. One-way and probabilistic sensitivity analyses were conducted and longer time horizons explored through Markov models. RESULTS: Epoetin alfa was associated with a cost per quality-adjusted life year (QALY) gained of $89,958 compared with standard care at 1 year. One-way sensitivity analyses indicated that results were sensitive to plausible ranges of mortality risk, risk of thrombosis, relative risk of mortality, relative risk of thrombosis, and quality of life estimates. Cost-effectiveness acceptability curves generated from probabilistic sensitivity analysis indicated that the probability that epoetin alfa would be considered attractive ranged from 0% to 85% over a willingness-to-pay range of $25,000 to $120,000/QALY. Consideration of lifetime time horizons reduced the cost per QALY gained to $7,203, but results were sensitive to the effect of epoetin alfa on mortality. CONCLUSION: Although the cost per QALY gained with epoetin alfa use may fall into an acceptable range, there is significant uncertainty about its true cost-effectiveness. If data regarding long-term efficacy and safety are confirmed in future trials, epoetin alfa could potentially be cost-effective in this population. LEVEL OF EVIDENCE: Economic analysis, level I.

Acute dialysis risk in living kidney donors.

BACKGROUND: Reduced kidney function confers a higher risk of acute kidney injury at the time of an inciting event, such as sepsis. Whether the same is true in those with reduced renal mass from living kidney donation is unknown. METHODS: We conducted a population-based matched cohort study of all living kidney donors in the province of Ontario, Canada who underwent donor nephrectomy from 1992 to 2009. We manually reviewed the medical records of these living kidney donors and linked this information to provincial health care databases. Non-donors were selected from the healthiest segment of the general population. RESULTS: There were 2027 donors and 20 270 matched non-donors. The median age was 43 years (interquartile range 34-50) and individuals were followed for a median of 6.6 years (maximum 17.7 years). The primary outcome was acute dialysis during any hospital stay. Reasons for hospitalization included infectious diseases, cardiovascular diseases and hematological malignancies. Only one donor received acute dialysis in follow-up (6.5 events per 100 000 person-years), a rate which was statistically no different than 14 non-donors (9.4 events per 100 000 person-years). CONCLUSIONS: These results are reassuring for the practice of living kidney donation. Longer follow-up of this and other donor cohorts will provide more precise estimates about this risk.